The subject matter described herein relates generally to turbine engines and more particularly, to fuel nozzle assemblies for use with turbine engines.
At least some known gas turbine engines ignite a fuel-air mixture in a combustor assembly to generate a combustion gas stream that is channeled to a turbine via a hot gas path. Compressed air is delivered to the combustor assembly from a compressor. Known combustor assemblies include a combustor liner that defines a combustion region, and a plurality of fuel nozzle assemblies that facilitate fuel and air delivery to the combustion region. The turbine converts the thermal energy of the combustion gas stream to mechanical energy used to rotate a turbine shaft. The output of the turbine may be used to power a machine, for example, an electric generator or a pump.
At least some known fuel nozzle assemblies include tube assemblies or micro-mixers that facilitate mixing substances, such as diluents, gases, and/or air with fuel to generate a fuel mixture for combustion. Such fuel mixtures may include a hydrogen gas (H2) that is mixed with fuel such that a high hydrogen fuel mixture is channeled to the combustion region. During combustion of fuel mixtures, known combustors may experience flame holding or flashback in which the flame that is intended to be confined within the combustor liner travels upstream towards the fuel nozzle assembly. Such flame holding/flashback events may result in degradation of emissions performance and/or overheating and damage to the fuel nozzle assembly, due to the extremely large thermal load.
In addition, during operation of some known combustor assemblies, combustion of high hydrogen fuel mixtures may form a plurality of eddies adjacent to an outer surface of the fuel nozzle assembly that increase the temperature within the combustion assembly and that induce a screech tone frequency that causes vibrations throughout the combustor assembly and fuel nozzle assembly. The increased internal temperature and vibrations may cause wear and/or may shorten the useful life of the combustor assembly.